1. Field of the Invention
This invention relates generally to semiconductor products manufacturing, and, more particularly to a method and means for automated manufacturing model building and updating.
2. Description of the Related Art
The technology explosion in the manufacturing industry has resulted in many new and innovative manufacturing processes. Today""s manufacturing processes, particularly semiconductor manufacturing processes, call for a large number of important steps. These process steps are usually vital, and, therefore, require a number of inputs that are generally fine-tuned to maintain proper manufacturing control.
The manufacture of semiconductor devices requires a number of discrete process steps to create a packaged semiconductor device from raw semiconductor material. The various processes, from the initial growth of the semiconductor material, the slicing of the semiconductor crystal into individual wafers, the fabrication stages (etching, doping, ion implanting, or the like), to the packaging and final testing of the completed device, are so different from one another and specialized that the processes may be performed in different manufacturing locations that contain different control schemes.
One of the many aspects of semiconductor manufacturing is overlay control. Overlay is one of several important steps in the lithography area of semiconductor manufacturing. Overlay control involves measuring the misalignment between two successive patterned layers on the surface of a semiconductor device. Generally, minimization of misalignment errors is important to ensure that the multiple layers of the semiconductor devices are connected and functional. As technology facilitates smaller critical dimensions for semiconductor devices the need for reducing misalignment errors increases dramatically.
Generally, photolithography engineers currently analyze the overlay errors a few times a month. The results from the analysis of the overlay errors are used to manually make updates to control or ASM settings. Some of the problems associated with the current methods include the fact that the ASM settings are only updated a few times a month. Furthermore, currently the ASM updates are performed manually. Therefore, manufacturing models 140 are generally created manually and updated manually, which can compromise the accuracy of manufacturing processes.
Generally, a set of processing steps is performed on a lot of wafers on a semiconductor manufacturing tool called a stepper. The stepper communicates with a manufacturing framework or a network of processing modules. The manufacturing framework is connected to an equipment interface. The equipment interface is connected to a machine interface to which the stepper is connected, thereby facilitating communications between the stepper and the manufacturing framework. The machine interface interacts with an automatic process control (APC) system. The APC system initiates a control script, which can be a computer program that automatically retrieves the data needed to execute a manufacturing process. The input parameters that control the manufacturing process are revised periodically in a manual fashion. As the need for higher precision manufacturing processes are required, improved methods are needed to revise input parameters that control manufacturing processes in a more automated and timely manner. One important method of improving semiconductor manufacturing is by improving the manufacturing models that are used to perform semiconductor manufacturing processes. Currently, production data are generally analyzed manually and manufacturing models are redefined slowly.
The present invention is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.
In one aspect of the present invention, a method is provided for performing automated development and update of a manufacturing model for a manufacturing process. An initial manufacturing model is developed. Tolerances of the manufacturing model are expanded using additional production data. The manufacturing model is re-developed using the expanded tolerances.
In another aspect of the present invention, an apparatus is provided for performing automated development and updating of a manufacturing model for a manufacturing process. The apparatus of the present invention comprises means for developing an initial manufacturing model, means for expanding tolerances of the manufacturing model using additional production data, and means for re-developing the manufacturing model using the expanded tolerances.